The invention generally relates to misting and watering system controllers and, in particular, to a controller having a light sensitive detector for turning on the misting and watering system before, at or after dawn and for turning off the misting and watering system before, at or after dusk.
Misting or watering system controllers are used in the horticultural industry to control the application of water to plants, including the application of a fine mist to delicate plants such as root plant cuttings. Since such plants are often delicate and subject to over or under watering, accurate watering control is desired. Further, since the amount of light on the plants affects the amount of water that actually reaches the roots of the plants, a system is needed that provides accurate watering control with respect to sunrise and sunset.
Presently, system controllers are available that have a photodetector for detecting light and that determine a time corresponding to when the sun rose in the morning and when the sun set in the evening based on the detected light. In turn, the controllers selectively start a misting or watering sequence at some time after sunrise and selectively stop the sequence at some time after sunset.
Often, however, a misting or watering sequence beginning before sunrise and/or ending before sunset is desired. For this reason, there is a need for a controller which is capable of selectively starting misting or watering operation in a plurality of zones a period of time before, at or after sunrise and selectively stopping the misting or watering operation a period of time before, at or after sunset. As such, a system controller which is able to accurately and reliably predict the next sunrise and the next sunset is needed.
Further, the available controllers that include a photodetector are often subject to errors associated with transitory occurrences. As an example, clouds passing overhead or objects covering the photodetector may cause a false indication of sunset. Similarly, light from transitory sources such as lightning may cause a false indication of sunrise. Therefore, a controller is needed which provides validation of detected transitions from day to night and from night to day.